Final answer:
There are two phenotypes present between the genotypes HH, Hh, and hh: 'Tall' for both HH and Hh genotypes, and 'Dwarf' for the hh genotype, because the presence of the dominant allele (H) for tallness masks the expression of the recessive allele (h) for dwarfness.
Step-by-step explanation:
The question asks how many phenotypes are present between the genotypes HH, Hh, hh. A phenotype is an organism's observable physical characteristics, which are influenced by the organism's genotype, or genetic constitution. In the context of the genotypes provided (which may refer to a trait like plant height, with 'H' indicating a dominant allele for tallness, and 'h' the recessive allele for dwarfness), there are two potential phenotypes:
- Tall - represented by the genotypes HH (homozygous dominant) and Hh (heterozygous)
- Dwarf - represented by the genotype hh (homozygous recessive)
Therefore, when the dominant trait is tallness, both the homozygous dominant (HH) and the heterozygous (Hh) organisms will exhibit the tall phenotype. Only the homozygous recessive (hh) organisms will display the dwarf phenotype. As a result, there are two different phenotypes present among these three genotypes.
This answer correlates with the basic principles of inheritance, mentioned in Mendelian genetics, that state the presence of a dominant allele (H) masks the expression of a recessive allele (h). It's essential to note that different genotypes can result in the same phenotype if a dominant allele is present.